This week's weird fish is another from the depths of the world's oceans. Bathypterois grallator, commonly known as the Tripod fish, is a true oddity.

Usually found at depths of between 750 and 4700m, they get their name from the way they hunt.

The fish uses greatly elongated pelvic and lower caudal fin rays to stand raised on the sea bed like a tripod. Once settled it turns its head into the direction of water movement and waits motionless in the dark until it detects potential prey items using its extended pectoral fins, which it holds out above its head like antenna.

These fins then direct the food towards its huge mouth. This method of hunting is extremely low in energy use and ideal for a predator living in the virtual desert of the deep ocean.

Living in perpetual darkness, the fish's eyes have disappeared almost completely.

Its scientific name is derived from the Greek, 'bathy' from bathus meaning deep and 'pterois' meaning feathery (Pterois is also a genus of marine fish that includes the lionfish, Pterois volitans which also has feathery fins), while 'grallator' means stilt walker.

Growing to around 30cm/12in, their specialised fins are almost three times that length.

Tripod fish are synchronous hermaphrodites, being able to produce both sperm and eggs, another adaptation to living a solitary existence in such a sparsely populated environment. If two fish do meet they will breed, but they are capable of producing offspring by themselves.

Tripod fish are widely distributed throughout most of the world's deep oceans.